It is an electrically operated, electronically diverted, hydraulically actuated, diaphragm valve. The flow into and out of the upper operating chamber is controlled by the two-way solenoid pilot. The electronic control determines whether the opening solenoid or the closing solenoid is operated. The change in valve position is dependent upon which solenoid is operated and the duration of the energized period.
The two way solenoid operate the main valve. The first connects the main valve inlet to the diaphragm chamber and when it is open, causes the main valve to close. The second solenoid connects the main valve outlet and, when it is open allows the main valve to open. A needle valve is provided in series with each solenoid, giving separate adjustment of the valve opening and closing speed.